package com.fang.offer.tree;

import java.util.Arrays;

import com.fang.tree.print.TreeNode;
import com.fang.tree.print.TreePrinter;

/**
 * <pre>
 *题目描述
 *输入某二叉树的前序遍历和中序遍历的结果，请重建出该二叉树。假设输入的前序遍历和中序遍历的结果中都不含重复的数字。
 *例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6}，则重建二叉树并返回。
 * </pre>
 * 
 */
public class ReConstructBinaryTree {

	public static void main(String[] args) {
		int[] pre = { 1, 2, 4, 7, 3, 5, 6, 8 };
		int[] in = { 4, 7, 2, 1, 5, 3, 8, 6 };
		TreeNode tree = ReConstructBinaryTree.reConstructBinaryTree(pre, in);
		int[][] dest = TreePrinter.printTree(tree);
		TreePrinter.printArrays(dest);
	}

	public static TreeNode reConstructBinaryTree(int[] pre, int[] in) {
		if (pre.length == 0 || in.length == 0) {
			return null;
		}
		TreeNode root = new TreeNode(pre[0]);
		// 此处应该判断Index是否存在
		int index = findIndex(in, pre[0]);
		// 计算左子树
		root.left = reConstructBinaryTree(Arrays.copyOfRange(pre, 1, index + 1), Arrays.copyOfRange(in, 0, index));
		// 计算右子树
		root.right = reConstructBinaryTree(Arrays.copyOfRange(pre, index + 1, pre.length),
				Arrays.copyOfRange(in, index + 1, in.length));
		return root;
	}

	private static int findIndex(int[] data, int temp) {
		for (int i = 0; i < data.length; i++) {
			if (data[i] == temp)
				return i;
		}
		return -1;
	}
}
